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Hydraulic Filter

Hydraulic filters are available in a multitude of shapes, sizes, micron ratings and construction materials. Hydraulic filters provide inbuilt protection and minimize hydraulic system breakdowns that are quite often caused by contamination.

Efficient filtration helps prevent system failure and makes a significant contribution to low cost of ownership. These are fitted for both low and high pressure hydraulic applications. The filter used in hydraulic system should be subjected to periodic and routine cleaning and maintenance. The life of a filter in a hydraulic system depends primarily on the system pressures, level of contamination and nature of contaminants. Hydraulic filters are essential requirement for proper functioning of a hydraulic machine.

Use of Hydraulic Filters

One of the main cause of failure or poor functioning of a hydraulic system is contamination of hydraulic oil or fluid. Hydraulic filters are used for handling and removing contamination from petroleum-based oils, synthetic hydraulic fluids, emulsions, lubrication oils etc. With the increased use of hydraulic systems and components, there is also the growing importance of system maintenance. It is very essential to maintain the filtration of the fluid. Since a hydraulic system runs at higher pressures and faster cycle times, with closer tolerances in control valves and moving parts, greater system pressure and increased sensitivity to pollution and contamination, the efficiency and reliability of a hydraulic system depends on proper filtration. To ensure a trouble free operation, a proper filter is required. Infact installing, cleaning and maintaing a proper hydraulic filter is the most cost effective way and easiest way to maintain the entire system.

Types of Filters

In a hydraulic system, there are two main types of filters that are frequently used. These are: Surface filters: These are simple screens used to clean oil passing through the pores. The dirty unwanted particles are collected at the top surface of the screens when the oil is passed. Depth filters: These are thick walled filter elements through which the oil is made to pass retaining the undesirable foreign particles. The capacity of depth filter is much higher than surface filters as much finer materials have a chance of being arrested by these filters.

Filters can also be classified as:

(a) Full-flow filter
In a hydraulic system it is necessary that all the flow must be through the filter element. So, the oil must enter the filter element at its inlet side and sent out through the outlet after crossing the filter element fully. In case of full flow filtration, the filter is sized to accommodate the entire oil flow at that part of the circuit.
(b) By-pass filter
At times, the entire volume of oil need not be filtered and thus, only a portion of the oil is passed through the filter element. The main portion is directly passed without filtration through a restricted passage.